Reset QFileDevicePrivate::cachedSize on file close

When a QFile object is reused, the atEnd() method may return incorrect
values. The reason for this is that QFileDevicePrivate::cachedSize is
not cleared. Setting cachedSize = 0 in the close() method fixes this issue.

Task-number: QTBUG-57698
Change-Id: I828a2cf844e98d581098f2c781fa47d2cd3275ce
Reviewed-by: Alex Trotsenko <alex1973tr@gmail.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 62 insertions, 0 deletions

diff --git a/tests/auto/corelib/io/qfile/tst_qfile.cpp b/tests/auto/corelib/io/qfile/tst_qfile.cpp
index 2ef4c2c6a1..34ad2813b0 100644
--- a/tests/auto/corelib/io/qfile/tst_qfile.cpp
+++ b/tests/auto/corelib/io/qfile/tst_qfile.cpp
@@ -243,6 +243,8 @@ private slots:
     void invalidFile_data();
     void invalidFile();
 
+    void reuseQFile();
+
 private:
     enum FileType {
         OpenQFile,
@@ -3436,5 +3438,65 @@ void tst_QFile::autocloseHandle()
     }
 }
 
+void tst_QFile::reuseQFile()
+{
+    // QTemporaryDir is current dir, no need to remove these files
+    const QString filename1("filegt16k");
+    const QString filename2("file16k");
+
+    // create test files for reusing QFile object
+    QFile file;
+    file.setFileName(filename1);
+    QVERIFY(file.open(QIODevice::WriteOnly));
+    QByteArray ba(17408, 'a');
+    qint64 written = file.write(ba);
+    QCOMPARE(written, 17408);
+    file.close();
+
+    file.setFileName(filename2);
+    QVERIFY(file.open(QIODevice::WriteOnly));
+    ba.resize(16384);
+    written = file.write(ba);
+    QCOMPARE(written, 16384);
+    file.close();
+
+    QVERIFY(file.open(QIODevice::ReadOnly));
+    QCOMPARE(file.size(), 16384);
+    QCOMPARE(file.pos(), qint64(0));
+    QVERIFY(file.seek(10));
+    QCOMPARE(file.pos(), qint64(10));
+    QVERIFY(file.seek(0));
+    QCOMPARE(file.pos(), qint64(0));
+    QCOMPARE(file.readAll(), ba);
+    file.close();
+
+    file.setFileName(filename1);
+    QVERIFY(file.open(QIODevice::ReadOnly));
+
+    // read first file
+    {
+        // get file size without touching QFile
+        QFileInfo fi(filename1);
+        const qint64 fileSize = fi.size();
+        file.read(fileSize);
+        QVERIFY(file.atEnd());
+        file.close();
+    }
+
+    // try again with the next file with the same QFile object
+    file.setFileName(filename2);
+    QVERIFY(file.open(QIODevice::ReadOnly));
+
+    // read second file
+    {
+        // get file size without touching QFile
+        QFileInfo fi(filename2);
+        const qint64 fileSize = fi.size();
+        file.read(fileSize);
+        QVERIFY(file.atEnd());
+        file.close();
+    }
+}
+
 QTEST_MAIN(tst_QFile)
 #include "tst_qfile.moc"